The route goes from Bleilaf, Germany only because we camped there and leads through some great rural twisty roads to Prum. Watch the speed camera as you enter Prum but that is the only one you will see on this route.
Head from Prum down to the bikers cafe/bar at Dasburg which also has a handy fuel stop. From there continue on to vianden.
Mixture of very tight to long sweeping bends with the odd straight bit.
Enjoy it.